As is well known, the processing of silver halide photographic light-sensitive materials typically includes a washing step. It is desirable to reduce the amount of water for the washing step to protect the environment, to conserve water resources, or to reduce processing costs. For this purpose, S. R. Goldwasser, "Water Flow Rates in Immersion -Washing of Motion Picture Film", SMPTE, 64, pp. 248-253 (May, 1955), for example, discloses a method of reducing the amount of water in the washing step, in which a plurality of washing tanks are used and water is flowed countercurrently. This method is now employed as an effective means in various types of automatic developing machines. This method has the disadvantages that the washing water contaminated during the processing with iron ions from the bleaching step and thiosulfates from the fixing step is very unstable. Furthermore, if the amount of the washing water is greatly decreased, the resident time of the washing water is undesirably lengthened, and various precipitates and floating matter are formed. These precipitates and floating matter can attach to the light-sensitive material, thereby contaminating it, or cause other difficulties such as plugging or contaminating a filter of the automatic developing machine.
In order to overcome the above problems, various techniques to prevent precipitates from forming in the washing water have been proposed. For example, L. E. West, "Water Quality Criteria", Phot. Sci. and Eng., Vol. 9, No. 6 (1965), discloses the addition of chelating agents and biocides.
In addition, Japanese Patent Application (OPI) Nos. 8542/82, 105145/83 and 157244/82 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application open to public inspection") describe the addition of various biocides. These compounds, however, are poor in solubility, or unsuitable from a viewpoint of safety, or have an insufficient effect of preventing precipitation, and thus fail to provide satisfactory results. Incorporation of chelating agents is described in Japanese Patent Application (OPI) Nos. 8542/82, 58143/82, 132146/82 and 18631/83. These chelating agents, however, are insufficient in preventing precipitation, or exert adverse influences on the image stability, and consequently also fail to provide satisfactory results. In addition, a method of adding sulfites and chelating agents in combination is described in Japanese Patent Application (OPI) Nos. 97530/82, 88738/84 and 88739/84. These combinations, however, are also unsatisfactory for the efficient prevention of precipitation.